Money Market Funds vs. HYSA: Which Yields More?

For years, cash savings earned practically zero interest. Now, the financial environment has shifted dramatically. Savers can finally generate significant passive income on their cash reserves, but choosing where to park that money has become more complex. Two of the most popular options are High-Yield Savings Accounts (HYSAs) and Money Market Funds (MMFs). While they look similar on the surface, they function differently regarding safety, tax treatment, and how they generate returns.

Defining the Contenders

Before comparing yields, it is vital to understand the structural differences between these two vehicles. One is a bank deposit, while the other is an investment product.

High-Yield Savings Accounts (HYSAs)

An HYSA is a standard savings account offered by a bank. The primary difference between an HYSA and a traditional brick-and-mortar savings account is the interest rate. Because HYSAs are typically offered by online-only banks (like Ally, Marcus by Goldman Sachs, or SoFi), they have lower overhead costs and pass those savings to you in the form of a higher Annual Percentage Yield (APY).

Structure: Bank Deposit.
Insurance: FDIC insured up to $250,000 per depositor.
Rate Type: Variable. The bank sets the rate and can change it at any time.

Money Market Funds (MMFs)

A Money Market Fund is a type of mutual fund offered by brokerage firms like Vanguard, Fidelity, or Charles Schwab. These funds pool money from investors to buy short-term, low-risk debt securities. These securities typically include U.S. Treasury bills, certificates of deposit (CDs), and commercial paper.

Structure: Investment Fund (Mutual Fund).
Insurance: SIPC coverage (protects against brokerage failure, not investment loss). Not FDIC insured.
Rate Type: Variable based on the current market rates of the underlying debt. This is usually expressed as a “7-Day SEC Yield.”

Note: Do not confuse a Money Market Fund with a Money Market Account (MMA). An MMA is a bank deposit similar to a savings account, whereas a Fund is an investment product.

Analyzing the Yields: The Numbers Game

Historically, Money Market Funds tend to offer slightly higher yields than HYSAs, though the gap fluctuates.

How HYSAs Calculate Return

HYSA rates are determined by the bank’s internal pricing committees. While they are influenced by the Federal Reserve’s benchmark rate, banks often lag behind Fed hikes. They want to keep their profit margins high, so they may be slow to raise rates for customers.

Current Range: As of late 2023 and entering 2024, competitive HYSAs are offering APYs between 4.30% and 5.30%.
Examples: Marcus by Goldman Sachs, Capital One 360, and CIT Bank Platinum Savings.

How MMFs Calculate Return

Money Market Funds track the Federal Funds Rate much more closely. Because the fund simply passes through the interest earned on the underlying bonds (minus a small expense ratio), the yield reacts almost immediately to market changes.

Current Range: Top-tier Money Market Funds are yielding between 4.75% and 5.40%.
Examples: Vanguard Federal Money Market Fund (VMFXX) and Fidelity Government Money Market Fund (SPAXX).

The Verdict: In a high-interest-rate environment, Money Market Funds generally edge out HYSAs by 0.25% to 0.50%. On a $10,000 balance, this difference is roughly $25 to $50 per year.

The Hidden Factor: Tax Efficiency

The advertised yield does not tell the whole story. The “real” return depends heavily on your tax bracket and where you live. This is where Money Market Funds often become the superior choice for high-earners.

Interest earned from a standard HYSA is fully taxable at both the federal and state levels. If you live in a state with high income tax (such as California, New York, or New Jersey), a 5.00% return might look more like 4.50% after state taxes are deducted.

However, specific Money Market Funds invest exclusively in U.S. Treasury obligations. The income generated from U.S. Treasuries is generally exempt from state and local income taxes.

The Math: If you are in a 9% state tax bracket, a Treasury-only MMF (like Vanguard’s VUSXX) yielding 5.20% provides a higher “tax-equivalent yield” than an HYSA yielding 5.50%.

Risk Analysis: FDIC vs. Breaking the Buck

Safety is usually the priority for cash savings. Here lies the most significant distinction.

The HYSA Safety Net

HYSAs are arguably the safest place to put cash. If the bank fails (like Silicon Valley Bank did), the Federal Deposit Insurance Corporation (FDIC) steps in. You are guaranteed to get your money back, up to $250,000 per depositor, per bank. There is virtually zero risk of losing principal.

The MMF Risk Profile

Money Market Funds are considered “cash equivalents” and are extremely safe, but they carry a theoretical risk. MMFs try to maintain a Net Asset Value (NAV) of $1.00 per share. This means if you put in $1, you should be able to take out $1 plus interest.

However, in extreme financial catastrophes, a fund could “break the buck,” meaning the share price drops below $1.00.

Historical Precedent: This happened in 2008 with the Reserve Primary Fund due to exposure to Lehman Brothers debt.
Modern Regulation: Since 2008, regulations have tightened significantly. Government MMFs (which invest in Treasuries) are safer than Prime MMFs (which invest in corporate debt).
SIPC Protection: Brokerages have SIPC insurance. This protects you if the brokerage firm itself goes bankrupt and your assets go missing. It does not protect you if the value of the fund drops due to poor investment performance.

Liquidity and Convenience

How quickly can you access your cash?

HYSA: Highly liquid. You can transfer money to your checking account instantly or within one business day. Some accounts, like those from SoFi or Ally, allow you to write checks or use an ATM card directly against the savings balance.
MMF: Slightly less liquid. Because it is a mutual fund, you technically have to “sell” your shares to get cash. This usually settles in one business day (T+1). You generally cannot swipe a debit card against a Money Market Fund unless your brokerage offers a specific cash management feature tied to it.

When to Choose Which

Choose a High-Yield Savings Account (HYSA) if:

You want absolute zero risk (FDIC insurance).
You need the money for immediate expenses or overdraft protection.
You want a simple user experience without opening a brokerage account.

Choose a Money Market Fund (MMF) if:

You already have a brokerage account (Vanguard, Fidelity, Schwab).
You live in a high-tax state and want to utilize Treasury funds to save on state taxes.
You are holding “dry powder” (cash) waiting to invest in the stock market.
You want to squeeze every possible basis point of yield out of your savings.

Frequently Asked Questions

Does a Money Market Fund cost money to own? Yes. All mutual funds have an “expense ratio.” This is the fee the fund manager charges to run the fund. For example, Vanguard’s VMFXX has an expense ratio of roughly 0.11%. However, the yields you see advertised (like the 7-day SEC yield) are net of fees. This means the fee has already been subtracted from the return you see.

Can I lose all my money in a Money Market Fund? It is extremely unlikely to lose all your money. The worst-case scenario typically involves the fund value dropping slightly below $1.00 (e.g., to $0.97). While possible, government-backed money market funds are considered one of the safest investments available outside of FDIC-insured products.

Why is the rate on an MMF called the “7-Day SEC Yield”? Unlike a bank APY which predicts forward-looking annual returns, the 7-Day SEC Yield is backward-looking. It calculates the average income the fund earned over the last 7 days and annualizes it. It provides the most accurate snapshot of what the fund is currently paying.

Are Money Market Funds locked? No. Unlike a Certificate of Deposit (CD), your money is not locked up for a set term. You can sell your shares and withdraw your cash at any time, usually receiving the funds within one business day.